Sendmail SMTP AUTH

Hi, has anyone sendmail SMTP AUTH running? My Problem ist that I can't authenticate through an unencrypted channel (i.e. port 25). In my mail log is only mentioned that no mail has made and that the connection timed out. My Browser offers me multiple times the password screen (Netscape 6.2). Can you help me? Ciao :-( Robert Rottscholl - DE